I tested the 5506 Bios (via .exe) today and it looks like that it is total crap.
It takes 5min to go past POST and it stopped there flickering full screen.
Back to 5456 (via recovery) everything works fine.
Updateing to 5506 (via recovery) 5min till POST screen, but it boot windows.
The 5456 bios is the best for me atm, because it has the s3 lan fix included and don't take 5min to get past POST.
The little flickering cursor before and after POST-Screen looks normal for me. It was there for me since I get the board.
win7 x64 pro
6gb kingston hyperx
samsung f1 1tb
wd ears 2tb